1. Field of the Invention
An aspect of this disclosure relates to a module and a method of manufacturing the module.
2. Description of the Related Art
There exists a module including a substrate and a semiconductor device mounted on the substrate. Such a module, for example, has a hollow structure and includes two semiconductor devices stacked in a box-shaped recess formed by a bottom plate and side walls of a substrate, and a cover plate provided over the recess (see, for example, Japanese Laid-Open Patent Publication No. 2005-101192).
When a mounting area ratio is defined as a ratio of an area of a semiconductor device mounted on a substrate to an area of the substrate, in order to increase the mounting area ratio of a module having the above-described structure without changing the size of the semiconductor device, it is necessary to reduce the area of the substrate by reducing the thickness of side walls of the substrate. However, reducing the thickness of the side walls may reduce the rigidity of the module and is therefore not preferable. Also, with the above-described structure, because a capillary may interfere with the side walls when wire-bonding the semiconductor device, there is a limit in reducing the area of the substrate.
There also exists a module having a hollow structure that is formed by attaching an inverted-box-shaped cover to a flat substrate to cover a semiconductor device mounted on the substrate. In this case, a margin for attaching the cover is necessary on the substrate, and therefore it is difficult to increase the mounting area ratio by reducing the area of the substrate.